Mechanical Isolation
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
Mechanical isolation is a prezygotic barrier in which two related species' reproductive structures do not physically fit together, preventing mating.
Show
Male damselflies of different species have differently shaped reproductive organs that do not fit another species' female structures.
Watch for
Mechanical isolation blocks mating through structural mismatch — distinct from gametic isolation, which blocks fertilization after mating occurs.